1. Field of the Invention
Embodiments relate to a satellite communication system and a method of cancelling interference in the satellite communication system to improve frequency efficiency by receiving and transmitting a signal using a same satellite channel in the satellite communication system using a satellite transponder.
2. Description of the Related Art
Due to a recent continuing increase in demand for broadband Internet services and emergency communication networks using Internet protocol (IP)-based satellite communication networks, countries including the United Kingdom and Japan are promoting related policies for wide distribution of satellite-based broadband communication services to reduce an information gap and construct infrastructures for ultra high-speed Internet. However, due to a relatively high rental cost for a satellite communication frequency, expansion of a satellite-based communication service may be limited. Thus, there is a desire for technology for effectively using a satellite communication frequency resource.
In related arts, a satellite communication system may measure, in advance, and store a characteristic of a travelling wave tube amplifier (TWTA), for example, an amplitude modulation (AM)/AM or an AM/phase modulation (PM), restore a signal to be received from a satellite transponder through a demodulation process, apply the TWTA characteristic to the restored signal, and extract a desired signal, for example, a terminal signal, by eliminating, from the received signal, interference, for example, a central station signal returning to a central station by a satellite.
In the related arts, however, only a TWTA characteristic of a central station may be compensated for, and only a TWTA characteristic in an initial installation may be stored and compensated for. Thus, a change in the characteristic occurring due to performance deterioration in a long-term operation may not be compensated for.
Thus, there is a desire for technology for estimating a nonlinear characteristic of a high power amplifier (HPA) at a central station and a satellite, for example, a satellite transponder, in an initial installation, and eliminating interference from a received signal, and thereby compensating for a change in such a characteristic in a long-term operation and eliminating interference in a satellite communication system using a same satellite channel.